I believe I have a short or some other electrical issue in my 89 f250 7.3L. The biggest problem is whenever I shift (automatic) from Drive to either Park or Reverse it oftens kills the motor; just like it's turning the key off. While driving, if I hit a bump the radio and heater fan kicks off until which time I wiggle the gear selector and it comes back on. I'm just curious if others have had this problem and what they did to fix it. Thanks.

 

The killing motor sounds like a TC problem and just stalls the motor. When the motor dies do lights go off? or on?

 

I would be willing to bet your Ignition wire is causing the problem along with some accessory wires. I would take apart the steering column and do some investigating.

 

no wires run up the column. down at the bottom of the column under the dash is your ignition switch. there is a rod that goes from the key down to this. check the plug and make sure it isnt loose.